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PCT

WORLD INTELLECTUAL PROPERTY ORGANIZATION
International Bureau

INTERNATIONAL APPLICATION PUBLISHED AjgpER THE PATENT COOPERATION TREATY (PCT)

(51) International Patent Classification 7
C09J 183/07, B65B 9/04

(11) International Publication Number: WO 00/68336

(43) International Publication Date: 16 November 2000 (16J 1.00)

(21) International Application Number: PCT/US99/09945

(22) International Filing Date: 5 May 1999 (05.05.99)

(71) Applicant (for alt designated States except US): 3M INNO-

VATIVE PROPERTIES COMPANY [US/US]; 3M Center,
P.O. Box 33427, Saint Paul, MN 55133-3427 (US).

(72) Inventors; and

(75) Inventors/Applicants (for US only): KO, John, H. [US/US];
3576 Rae Lane, Woodbury. MN 55125 (US). MELANCON,
Kurt, C. [US/US]; 6480 North 125th Street, White Bear
Lake, MN 55110 (US). SCHULZ, Anita, L. (US/US]; 61
Glen H. Road, Dellwood, MN 551 10-1420 (US).

(74) Agents: ROGERS, James, A. et al.; Minnesota Mining and
Manufacturing Company, Office of Intellectual Property
Counsel, P.O. Box 33427. Saint Paul, MN 55133-3427
(US).

(81) Designated States: AE, AL, AM, AT, AU. AZ, BA, BB, BG.
BR, BY, CA, CH, CN, CU. CZ, DE. DK, EE, ES, FI, GB,
GD, GE, GH, GM, HR, HU, ID, IL P IN, IS, JP, KE, KG,
KP, KR, KZ, LC. LK. LR, LS, LT, LU. LV, MD, MG, MK,
MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE. SG, SI,
SK, SL, TJ, TM, TR, TT, UA, UG. US, UZ. VN, YU, ZA,
ZW, ARIPO patent (GH, GM. KE, LS, MW. SD, SL. SZ,
UG, ZW), Eurasian patent (AM. AZ, BY, KG, KZ, MD.
RU, TJ, TM). European patent (AT, BE, CH, CY, DE, DK,
ES, FI, FR, GB. GR, IE, IT, LU. MC, NL, PT, SE), OAPI
patent (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR,
NE. SN, TD, TG).

Published

With international search report.

(54) TiUe: SILICONE ADHESIVES, ARTICLES. AND METHODS

(57) Abstract

The present invention provides silicone-based adhesives, preferably pressure sensitive adhesives, adhesive articles, and methods.
Preferably the articles are cover tapes for analytical receptacles, such as microliter plates, microfluidic devices, and continuous
multi-reservoir carriers, or other analytical receptacles or biosensors, for example. Typically, such analytical receptacles are used in
bioanalytical applications and are designed for containing solids and fluids, including liquids, gases, powders, and gels, which may include
biological samples or organic solvents, for example.

FOR THE PURPOSES OF INFORMATION ONLY

Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.

Albania

Spain

Lesotho

Slovenia

Armenia

Finland

Lithuania

Slovakia

Austria

France

Luxembourg

Senegal

Australia

Gabon

Latvia

Swaziland

Azerbaijan

United Kingdom

Monaco

Chad

Bosnia and Herzegovina

Georgia

Repubtic of Moldova

Togo

Barbados

Ghana

Madagascar

Tajikistan

Belgium

Guinea

The former Yugoslav

Turkmenistan

Burkina Faso

Greece

Republic of Macedonia

Turkey

Bulgaria

Hungary

Mali

Trinidad and Tobago

Benin

Ireland

Mongolia

Ukraine

Brazil

Israel

Mauritania

Uganda

Belarus

Iceland

Malawi

United States of America

Canada

Italy

Mexico

Uzbekistan

Central African Republic

Japan

Niger

Viet Nam

Congo

Kenya

Netherlands

Yugoslavia

Switzerland

Kyrgyzstan

Norway

Z>V

Zimbabwe

C6te d'lvoire

Democratic People's

New Zealand

Cameroon

Republic of Korea

Poland

China

Republic of Korea

Portugal

Cuba

Kazakstan

Romania

Czech Republic

Saint Lucia

Russian Federation

Germany

Liechtenstein

Sudan

Denmark

Sri Lanka

Sweden

Estonia

Liberia

Singapore

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SILICONE AD HE S IVES, ARTICLES, AND METHODS

Field of the Invention

The invention relates to silicone adhesives, articles, and methods
of making and using. The adhesives are particularly useful on articles such as
cover tapes for analytical receptacles, such as microtiter plates, microfluidic
1 0 devices, discrete or continuous multi-reservoir carriers, or other analytical

receptacles, particularly those that are designed for holding a variety of liquids,
in bioanalytical applications, for example.

Background

1 5 Microtiter plates are well knowtffor use in handling liquid

materials in bioanalytical assays for multiple, rapid, low-volume analysis. A
typical screening technique combines an assay plate, having multiple
depressions or wells, with liquid handling hardware to provide a rapid,
automated system of analysis. In a current, standard analytical system, each

20 assay plate accommodates 96 wells, each well being addressable by suitably
programmed hardware. The capacity of each of the 96 wells is about 0.2
milliliter (ml) to about 0.4 ml. Smaller capacity wells lead to assay plates that
accommodate a larger number of samples. For example, assay plates containing
1536 wells, each with a capacity of less than 5 microliters (nl) are known.

25 These plates, with increased sampling capability, have demonstrated usefulness
in a variety of assays, including enzyme assays, receptor-ligand assays, and even
cell based assays. The increased number of sample wells, per assay plate,
demands increased precision of the hardware associated with analysis using
these assay plates.

30 Liquid handling for bioanalytical applications, using assay plates

of either the 96-well, 384-well, or the 1 536-well variety, may be viewed as a

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batch process with rate limitation due to the loading and positioning of the assay
tray. Possible improvement in the rate of sample analysis results from the use of
a continuous strip of material having sample wells molded along its length. U.S.
Pat. No. 4,883,642 (Bisconte) suggests such a strip or tape. The patent teaches a
5 continuous ribbon, which may be either smooth or suitably molded to

incorporate a plurality of micro-wells. Fixed biological sample analysis uses
smooth versions of the continuous ribbons while micro-well ribbons find use for
analyzing living biological samples. Two tracks, positioned along opposite
edges of the ribbon, provide addressable means for moving and positioning the

10 ribbon in a selected, precise location with adjustment accurate to 10 micrometers
(jim). The tracks may be coded using magnetic, optical, or computer methods,
for example, which allow manipulation and positioning of the ribbon. A dosage
syringe type of device, positioned using a step by step motor, distributes
biological samples in the micro-wells.

1 5 This continuous multi-reservoir carrier is useful in the automated

analysis of biological samples, such as histological sections. Protection of the
samples, whether applied to a smooth ribbon or contained in micro-wells may
use a self-adhesive film. The self-adhesive film covers the smooth film surface
or seals the openings to the individual micro-wells. It may be permeable or

20 impermeable to air.

U.S. Pat No. 5,721,136 (Finney et al.) teaches the use of a
multilayer sheet having a silicone adhesive thereon for use on vessels for
biochemical reactions. One layer provides strength and integrity for the film.
The second layer is a thick, in the range of about 2 mils to about 40 mils (50 urn

25 to 1 0 1 6 jim), deformable material with a very low tack surface. The elastic
nature of the second layer results in good seal when clamped down during
thermal cycling. The rubbery materials also provide a very low level of
adhesion. The peel force of the sheet from a polypropylene surface is reported
tobeintherangeof0.11N/dmto0.5N/dm(0.1 oz/in to 4.5 oz/in). Althougha

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low tack adhesive tape is desirable to prevent the tape from sticking to rubber
gloves commonly used in biological research, when applied to a microplate, for
example, low adhesion of thick, elastic adhesive tapes is likely to cause a high
evaporation rate and increase the incidence of cross-contamination during

5 storage and handling.

To increase cohesive strength and reduce contamination due to
residual adhesive, silicone may be cured or crosslinked by catalysts such as
peroxide or metallic salts at elevated temperatures. For example, benzoyl
peroxide requires a cure temperature of more than 150°C for the catalyst to be

1 0 functional. Consequently, a backing with low melting or softening point, such as
a polyethylene film, may be overly stretched or distorted dimensionally during
curing. To prepare a curable silicone tape, one common practice is to coat
curable silicones on a release liner consisting of a fluorosilicone coating and
PET (polyethylene terephthalate) backing. The tape is then* laminated with the

1 5 backings of low melting or softening point temperatures. Since release liners are
commonly used to process and to protect silicone adhesive surfaces, it is
important that the release force to separate the tape from the release liner be kept
at a low level to minimize distortion of the tape backing, particularly when the
release liner is removed during an automatic process.

20 U.S. Pat. No. 5,082,706 (Tangney) describes a silicone

PSA/fluorosilicone release laminate having a release force of less than 7.7 N/dm
(7 oz/in) from the fluorosilicone release layer and a peel adhesion of at least
46.4 N/dm (42.2 oz/in). This adhesive includes a tackifying resin (often referred
to as an MQ resin) containing two structural units, one of which is P^Si0 1/2

25 (often designated as M) and the other SiO^ (often designated as Q). As

discussed in The Handbook of Pressure-Adhes ive Technology, 2 nd Edition, (ed.
D. Satas, 1989) p. 510, the peel adhesion of silicone pressure sensitive adhesives
can be controlled by controlling the amount of tackifying resin. For example,
increasing the amount of tackifying resin increases the peel adhesion; however,

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there is typically a point at which the peel adhesion maximizes. Thus,
increasing the amount of tackifying resin beyond this point can cause peel
adhesion to decrease.

Summary of the Invention

What is needed are adhesives and adhesive articles, particularly
cover tapes for analytical receptacles, that provide an effective peel strength
from the materials that typically form analytical receptacles yet good release

10 from a release liner and preferably sufficiently low tack as to be suitable for use
with analytical receptacles. Such adhesives would be especially desirable if they
are substantially resistant to liquids, particularly organic solvents such as
dimethyl sulfoxide that are often used in bioan^ytical applications.

The present invention provides adhesives, preferably pressure

1 5 sensitive adhesives (PSAs), adhesive articles, and methods. Preferably, the
articles are cover tapes for analytical receptacles, such as microtiter plates,
microfluidic devices, and continuous multi-reservoir carriers, or other analytical
receptacles or biosensors, for example. Typically, such analytical receptacles
are used in bioanalytical applications and are designed for containing solids and

20 fluids, including liquids, gases, powders, and gels, which may include biological
samples or organic solvents, for example.

In preferred embodiments, cover tapes for such analytical
receptacles provide a sealing membrane so that each reservoir, such as a well or
channel, for example, is part of a sealed enclosure to retain the contents and/or

25 reduce evaporation and contamination of the contents of the receptacle.
Preferred cover tapes have sufficient transparency to allow for photometric
analysis and/or visual inspection and are substantially resistant to solvents
commonly used in bioanalytical applications, such as dimethyl sulfoxide
(DMSO), water, acetonitrile/water, methanol, ethanol, or mixtures thereof, for

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example. As used herein, a substantially solvent-resistant cover tape, and
particularly adhesive, is one that does not substantially swell or dissolve in the
solvent used in the particular application and does maintain sufficient adhesion
to the analytical receptacle.

5 In one embodiment, the present invention provides a silicone

adhesive, preferably, a pressure sensitive adhesive, which is prepared from
components including: (a) a polydiorganosiloxane having the general formula
R'R 2 SiO(R 2 SiO) n SiR 2 R 1 and a number average molecular weight of at least
20,000, wherein each R is independently a monovalent hydrocarbon group, each

10 R' is independently an alkenyl group, and n is an integer; (b) a
polydiorganosiloxane having the general formula

R 1 R 2 SiO(R 2 SiO) m (R'RSiO) n SiR 2 R' and a number average molecular weight of
less than 20,000, wherein each R and R 1 is independently a monovalent
hydrocarbon group, at least two R' groups are alkenyl groups, and m and n are

15 integers the sum of which provide an alkenyl equivalent weight of about 250 to
about 10,000; (c) an organopolysiloxane MQ resin which contains (R 2 ) 3 SiO w
units and Si0 2 units in a molar ratio in the range of 0.6: 1 to 1 : 1 , wherein each R 2
is independently selected from the group of alkyl groups, alkenyl groups, or
hydroxyl groups, wherein at least 95 mole percent of all R 2 groups are methyl

20 groups; (d) an organohydrogenpolysiloxane free of aliphatic unsaturation having
an average of at least 2 silicon-bonded hydrogen atoms in each molecule, in a
quantity sufficient to provide from 1 to 40 silicon-bonded hydrogen atoms per
alkenyl group in components (a) through (c); and (e) a Group VETO-containing
catalyst in a quantity sufficient to provide 0. 1 to 1 ,000 weight parts Group VHIB

25 metal for each one million weight parts of the combined quantity of

components (a) through (d). Methods of making and methods of using such
adhesives are also provided.

In another embodiment, the present invention provides an
adhesive article that includes a substrate having disposed on at least one major

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surface a silicone-based adhesive, preferably a pressure sensitive adhesive, of the
above formula. Adhesive articles include tapes, labels, and other sheeting useful
in various formats including medical, graphics, and analytical applications.

In yet another embodiment, the present invention provides an

5 analytical receptacle that includes a surface, preferably having at least one

reservoir therein, and a cover tape adhered to the surface; wherein the cover tape
includes a backing and an adhesive of the formula above disposed on at least one
major surface of the backing and in contact with the receptacle surface.

In still another embodiment, the present invention provides an

10 analytical receptacle that includes a surface comprising polypropylene,

polystyrene, or combination thereof, and a cover tape adhered to the surface;
wherein the cover tape includes a backing and an adhesive disposed on at least
one major surface of the backing and in contacfcwith the receptacle surface,
wherein the adhesive is prepared from components including: (a) a

1 5 polydiorganosiloxane having the general formula R^SiO^SiO^SiRjR 1
wherein each R is independently a monovalent hydrocarbon group, each R 1 is
independently an alkenyl group and n is an integer; (b) an organopolysiloxane
MQ resin which contains (R 2 ) 3 SiO l/2 units and Si0 2 units in a molar ratio in the
range of 0.6: 1 to 1: 1, wherein each R 2 is independently selected from the group

20 of alkyl groups, alkenyl groups, or hydroxyl groups, wherein at least 95 mole
percent of all R ? groups are methyl groups; (c) an organohydrogenpolysiloxane
free of aliphatic unsaturation having an average of at least 2 silicon-bonded
hydrogen atoms in each molecule, in a quantity sufficient to provide from 1 to
40 silicon-bonded hydrogen atoms per alkenyl group in component (a) and

25 component (b) if present; and (d) a Group VIOB-containing catalyst in a

quantity sufficient to provide 0. 1 to 1 ,000 weight parts Group VIEB metal for
each one million weight parts of the combined quantity of components (a)
through (c).

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In yet another embodiment, the present invention provides an
analytical receptacle that includes a surface and a cover tape adhered to the
surface; wherein the cover tape includes a backing and an adhesive disposed on
at least one major surface of the backing and in contact with the receptacle
5 surface, wherein the adhesive is prepared from components including: (a) a
polydiorganosiloxane having the general formula R , R 2 SiO(R,SiO) n SiR 2 R 1
wherein each R is independently a monovalent hydrocarbon group, each R 1 is
independently an alkenyl group and n is an integer; (b) an organopolysiloxane
MQ resin which contains (R^SiO,, units and SiO, units in a molar ratio in the
10 range of 0.6: 1 to 1:1, wherein each R 2 is independently selected from the group
of alkyl groups, alkenyl groups, or hydroxyl groups, wherein at least 95 mole
percent of all R 2 groups are methyl groups; (c) an organohydrogenpolysiloxane
free of aliphatic unsaturation having an average of at least 2 silicon-bonded
hydrogen atoms in each molecule, in a quantity sufficient to-provide from 1 to
1 5 40 silicon-bonded hydrogen atoms per alkenyl group in component (a) and
component (b) if present; and (d) a Group VinB-containing catalyst in a
quantity sufficient to provide 0. 1 to 1 ,000 weight parts Group VEIB metal for
each one million weight parts of the combined quantity of components (a)
through (c); wherein the adhesive when disposed on a fluorosilicone-coated
20 polyethylene terephthalate release liner and a propylene/ethylene copolymer
backing at a coating weight of 0.8 grams/154.8 cm 2 to form a laminate, and
when adhered to a glass plate, displays a 180° release force of no greater than
about 20 N/dm when measured at 30.5 cm/minute and room temperature.

The analytical receptacle can be in the form of a substantially
25 continuous tape or it can be in discrete shapes and sizes, preferably with one or
more reservoirs. For example, the analytical receptacle can be in the form of a
microliter plate, a microfluidic device comprising a substrate and one or more
channels therein, or a substantially continuous polymeric strip (i.e., tape)
comprising a plurality of reservoirs at predetermined intervals (preferably,

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uniformly spaced) along its length. Thus, the reservoir(s) can be in a wide
variety of shapes and sizes. Preferably, they form wells or channels.

The adhesive of the present invention can form a pattern on the
substrate (e.g., backing of a cover tape) or it can form a continuous layer on at
5 least one major surface thereof. It is preferably a pressure sensitive adhesive,
which unlike a heat activated adhesive, typically uses pressure to engage
adhesion and does not require the use of a heating device. Certain preferred
tapes of the present invention can also be conveniently repositioned to different
locations or repositioned to the same location for resealing purposes if desired.

Detailed Description of Preferred Embodiments

The present invention provides silicone-based adhesives,
preferably, pressure sensitive adhesives, articles on which such adhesives are
disposed (e.g., tapes), and methods of making and using such adhesives and

1 5 articles. One particularly preferred article is a cover tape for an analytical
receptacle. As used herein, analytical receptacles are devices that receive a
sample, reagent, or solvent. Preferably, the device is configured to receive a
volume of sample, reagent, or solvent, most preferably a microvolume. Such
preferred configurations include one or more reservoirs. Examples include

20 assay plate arrays (e.g., microtiter plates) and discrete or continuous (e.g., strip
or tape) structures containing a plurality of wells, channels, or other reservoirs.
Preferred analytical receptacles, without Anther modification, provide an open
system of one or more reservoirs (e.g., wells or channels) to which fluids may be
added directly. Open systems require careful control of evaporation and cross-

25 contamination, which limits their practical applications. Thus, cover tapes are
desirable as they result in closed systems that do not necessarily require
specialized sample transport and containment.

A cover tape is applied along the length and width of an
analytical receptacle to seal the receptacle, preferably the reservoir(s) of the

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receptacle. Preferably, this results in producing individually sealed enclosures.
Materials may be injected into or extracted from the closed reservoirs, through
the cover tape, using suitable hypodermic-type needles, for example, if so
desired. Preferred analytical receptacles can include one or more reservoirs.

5 They can be substantially continuous or discrete (i.e., noncontinuous) structures.
For example, an analytical receptacle can be in the form of a microtiter plate that
is conventionally used in bioanalytical methods. Alternatively, it can be a
microfluidic device or continuous multi-reservoir carrier, for example, which
can be cut into discrete (noncontinuous) pieces, if desired. Preferably,

10 conventional analytical receptacles are made of polyolefins, polystyrene, and/or
polycarbonate, for example, and more preferably, polypropylene and/or
polystyrene.

A cover tape of the present invention, which acts as a sealing
membrane, includes a silicone adhesive, preferably, a pressure sensitive silicone
1 5 adhesive, disposed on a backing. Preferably, the backing is made of a

transparent material to allow for photometric analysis and/or visual inspection.
A cover tape of the present invention preferably adheres well to materials of
which conventional analytical receptacles are made (preferably polyolefins,
polystyrene, polycarbonate, or combinations thereof, and more preferably,
20 polypropylene, polystyrene, or combinations thereof) and is preferably

repositionable (i.e., the adhesive permits repeated cycles in which materials are
alternatively bonded thereto and removed therefrom, while the adhesive is
permanently retained on the backing of the adhesive article), but does not allow
cross-contamination of sample materials in the individual reservoirs. Preferably,
25 the cover tape maintains adhesion during high and low temperature storage (e.g.,
about -80°C to about 200°C) while providing an effective seal against sample
evaporation (e.g., less than 5% loss within 24 hours as used in a analytical
quantitative analysis setting). Suitable cover tapes of the present invention allow
for puncture by needles, such as stainless steel needles, or plastic sampling

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pipette tips, for example, although cover tapes that resist puncture can also be
used. These puncture sites may or may not reclose. The ability to be punctured
and reclosed is typically controlled by the choice of backing material and/or
thickness of the adhesive (e.g., a 0.01 cm thick adhesive layer may flow

5 suffici ently to reclose a puncture site) .

Because use of the cover tape can expose the adhesive to fluid
contents of a reservoir, the choice of adhesive is of particular importance. Thus,
it is important that the cover tape, and particularly the adhesive composition,
does not substantially dissolve or otherwise react with solvents, such as dimethyl

10 sulfoxide (DMSO) and acetonitrile/water, used commonly in bioanalytical
research. Thus, preferred adhesives are substantially resistant to a wide variety
of solvents, such as DMSO, water, acetonitrile/water, methanol, ethanol, or
similar polar solvents, as well as mixtures thereof. That is, preferred adhesives
do not substantially swell or dissolve in the solvent used nrthe particular

1 5 application while they maintain sufficient adhesion to the analytical receptacle.

Furthermore, preferred adhesives are pressure-sensitive adhesives
with sufficient cohesive strength that they leave little or no residue on the
analytical receptacles or the needles or pipette tips after withdrawal from the
puncture hole in the cover tape. This adhesive also preferably exhibits low tack,

20 which serves to reduce adhesion of the cover tape to commonly used rubber
gloves made from latex or nitrile rubber (e.g., no greater than about 10 N/dm
peel force).

Preferred adhesives also are substantially biocompatible (i.e.,
substantially physiologically inert). As used herein, a biocompatible" material
25 is one that does not generally cause significant adverse reactions (e.g., toxic or
antigenic responses) when in contact with biological fluids and/or tissues, such
as tissue death, tumor formation, allergic reaction, inflammatory reaction, or
blood clotting, for example.

The adhesives of the present invention include silicones, which

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typically have excellent thermal and oxidative stability and a very broad service
temperature range (i.e., a temperature range in which the adhesive is useful) of
about -80°C to about 200°C. Silicone is also generally inert to a wide variety of
polar chemicals and solvents, for example, water, methanol, ethanol,

5 acetonitrile/water, and DMSO commonly used in bioanalytical testing.

Furthermore, silicones are substantially biocompatible and are used in various
medical devices. These properties make them excellent adhesives for use in, for
example, cover tapes for analytical receptacles that are used in bioanalytical
applications. However not all silicone adhesives in combination with all

1 0 backings have the appropriate balance of properties (e.g., peel force, release
force, and tack).

A silicone adhesive laminate disclosed in U.S. Pat. No. 5,082,706
(Tangney) includes an addition-cured silicone pressure sensitive adhesive on an
addition-cured fluorosilicone release coating. When thin backings are employed

1 5 in adhesive article constructions, it is desirable that upon separating the adhesive
article (e.g., cover tape) from the release liner, release be sufficiently low that
little if any permanent deformation of the backing occur. Thin backings (e.g.,
less than about 0.005 cm thick) and/or backings having low flexural modulus
(e.g., polyolefins), deform easily. Thus, release forces required to separate

20 adhesive articles based on such backings need to be very low to avoid inducing
permanent deformation or curl in the adhesive article.

Although the release force needed to separate the adhesive from
the fluorosilicone release coating of U.S. Pat. No. 5,082,706 (Tangney), after it
is cast onto and cured in contact with the release coating, is reported to have a

25 value of less than 200 grams per inch (7 .7 N/dm), while at the same time

displaying stable subsequent adhesiveness (46.4 N/dm from stainless steel) and
stable subsequent tack, commercially available materials do not generally
display sufficiently low release forces for many applications. For example, Dow
Coming 7657 silicone adhesive displays a release force from a Rexam CLPET-

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6J/000 transfer liner (fluorosilicone coating on a polyethylene terephthalate
backing available from Rexam Release Corp., Bedford, IL) of 7.1 N/dm (see
Example 1 for curing conditions). Although this is suitable for some
applications, it is not typically suitable for transfer of the adhesive to very thin
5 and/or fragile backings or in automated systems in which the release liner is
removed. Thus, compositions providing lower release (e.g., no greater than
about 5 N/dm) are particularly desirable for such applications.

The silicone adhesive of U.S. Pat. No. 5,082,706 is prepared
from the following components: (a) a polydiorganosiloxane having the general

10 formula R 1 R 2 SiO(R 2 SiO) n SiR 2 R 1 wherein each R is independently a monovalent
hydrocarbon group, each R 1 is independently an alkenyl group and n is an
integer; (b) an organopolysiloxane (often designated as an MQ resin) which
contains (R 2 ) 3 Si0 1/2 units (often designated as M units) and Si0 2 units (often
designated as Q units) in a molar ratio in the range of 0.6: 1 to 0.9: 1 , wherein

1 5 each R 2 is independently selected from the group of alkyl groups, alkenyl

groups, or hydroxyl groups, wherein at least 95 mole percent of all R 2 groups are
methyl groups; (c) an organohydrogenpolysiloxane free of aliphatic unsaturation
having an average of at least 2 silicon-bonded hydrogen atoms in each molecule,
in a quantity sufficient to provide from 1 to 40 silicon-bonded hydrogen atoms

20 per alkenyl group in component (a) and component (b) if present; and (d) a
platinum-containing catalyst in a quantity sufficient to provide 0.1 to 1,000
weight parts platinum for each one million weight parts of the combined
quantity of components (a) through (c).

For certain embodiments of the present invention, similar and

25 preferred adhesives can be used wherein: the hydrocarbon groups of the above
formula can be alkyl and alkenyl groups, etc., up to, for example, groups
containing 10 carbon atoms; the alkyl groups can be methyl, ethyl, propyl,
hexyl, etc., up to, for example, groups containing 10 carbon atoms; the alkenyl
groups can be vinyl, propenyl, hexenyl, etc., up to, for example, groups

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containing 10 carbon atoms; the molar ratio of M to Q units in the MQ resin is
in the range of 0.6: 1 to 1 : 1 ; and a Group VIIIB-containing metal catalyst.

Embodiments of the silicone adhesive of U.S. Pat No. 5,082,706
that contain higher levels of the MQ resin typically display lower release values

5 from the fluorosilicone liner, without significantly detrimentally affecting the
peel values from other substrates (generally, polyolefms, polystyrene,
polycarbonate, for example, and preferably, polypropylene and polystyrene).

Preferably, the level of MQ resin (and other components of the
adhesives described herein) can be adjusted to provide an adhesive, which when

1 0 disposed on a fluorosilicone-coated polyethylene terephthalate release liner and
a ethylene/propylene copolymer backing at a coating weight of 0.8 grams/154.8
cm 2 to form a laminate, and when the laminate is adhered to a glass plate,
displays a 1 80° release force of no greater than about 20 N/dm, more preferably,
no greater than about 15 N/dm, even more preferably, no greater than about 10

1 5 N/dm, and most preferably, no greater than about 5 N/dm, when measured at

o o

30.5 cm/minute and room temperature (about 25 C to about 30 C). Preferably,
the level of MQ resin (and other components of the adhesives described herein)
can also be adjusted to provide an adhesive, which when disposed on a
ethylene/propylene copolymer backing at a coating weight of 0.8 grams/154.8

20 cm 2 and adhered to a polypropylene plate, displays a 1 80 peel force of at least
about 5 N/dm, more preferably, at least about 10 N/dm, and most preferably, at
least about 1 5 N/dm, when measured at 30.5 cm/minute and room temperature
(about 25°C to about 30°C). Preferably, the peel force is no greater than about
50 N/dm.

25 Suitable types and amounts of the various adhesive components

described above are those that are disclosed in U.S. Pat. No. 5,082,706
(Tangney). Typically, the amount of MQ resin (i.e., one in which R 2 is an alkyl
group) needed to achieve desired levels of release and peel forces will depend on

WO 00/68336

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the amount of the polydiorganosiloxane having the general formula
R 1 R 2 SiO(R 2 SiO) n SiR 2 R 1 . Preferably, at least about 50 weight parts MQ resin
and no greater than about 70 weight parts MQ resin is used to achieve the
desired levels of peel and release forces, when the total weight parts (i.e., parts

5 by weight) of MQ resin plus polydiorganosiloxane having the general formula
R l R 2 SiO(R 2 SiO) n SiR 2 R 1 equals 100 parts.

Alternatively to, or in addition to, increasing the level of MQ
resin in the silicone adhesive of U.S. Pat. No. 5,082,706 to decrease the level of
release force, a low molecular weight vinyl-substituted siloxane can be added to

10 the composition. That is, the polydiorganosiloxane described above is actually
present as a high molecular weight component and a low molecular weight
component in these prefered embodiments of the adhesive. This low molecular
weight component can be added as a component of a commercially available
release modifier (e.g., Dow Corning SYL-OFF 7615 release modifier or General

1 5 Electric Silicones SL-6030) typically used to increase release. Thus, the use of
this material to decrease the release force is unexpected, particularly without
significantly adversely affecting the peel force.

Such silicone pressure sensitive adhesives are prepared from the
following components: (a) a polydiorganosiloxane having the general formula

20 R 1 R 2 SiO(R 2 SiO) n SiR 2 R l and a number average molecular weight of at least

20,000, wherein each R is independently a monovalent hydrocarbon group (such
as alkyl groups, alkenyl groups, etc., up to, for example, groups containing 10
carbon atoms), each R 1 is independently an alkenyl group (such as vinyl,
propenyl, hexenyl, etc., up to, for example, groups containing 10 carbon atoms),

25 and n is an integer, (b) a polydiorganosiloxane having the general formula
R I R 2 SiO(R 2 SiO) m (R I RSiO) n SiR 2 R 1 and a number average molecular weight of
less than 20,000, wherein each R and R 1 is independently a monovalent
hydrocarbon group (such as alkyl groups, alkenyl groups, etc. up to, for
example, groups containing 10 carbon atoms), at least two R 1 groups are alkenyl

WO 00/68336 PCT/US99/09945

groups (such as vinyl, propenyl, hexenyl, etc., up to, for example, groups
containing 10 carbon atoms), and m and n are integers the sum of which provide
an alkenyl equivalent weight of about 250 to about 10,000; (c) an
organopolysiloxane (designated as an MQ resin) which contains (R 2 ) 3 Si0 1/2 units

5 (designated as M units) and Si0 2 units (designated as Q units) in a molar ratio in
the range of 0.6: 1 to 1 : 1 , wherein R 2 is selected from the group of alkyl (such as
methyl, ethyl, propyl, hexyl, etc., up to, for example, groups containing 10
carbon atoms), alkenyl (such as vinyl, propenyl, hexenyl, etc., up to, for
example, groups containing 10 carbon atoms), or hydroxyl groups, wherein at

1 0 least 95 mole percent of all R 2 groups are methyl groups; (d) an

organohydrogenpolysiloxane free of aliphatic unsaturation having an average of
at least 2 silicon-bonded hydrogen atoms in each molecule, in a quantity
sufficient to provide from 1 to 40 silicon-bondqd hydrogen atoms per alkenyl
group in components (a) through (c); and (e) a Group VIIIB-containing catalyst

15 in a quantity sufficient to provide 0. 1 to 1 ,000 weight parts Group VIIIB metal
for each one million weight parts of the combined quantity of components (a)
through (d). Preferably, such compositions include both nonfunctional and
functional MQ resins, particularly alkenyl-functional MQ resins.

Suitable polydiorganosiloxanes having the general formula

20 R 1 R 2 SiO(R 2 SiO) n SiR 2 R 1 and a number average molecular weight of at least

20,000 are commercially available from sources such as Gelest Inc., Tullytown,
PA. Examples are disclosed in U.S. Pat No. 5,082,706 (Tangney). For
particularly preferred embodiments, the molecular weight is preferably at least
about 50,000, more preferably, at least about 100,000, and most preferably, at

25 least about 250,000.

Suitable polydiorganosiloxane of the general formula
R , R 2 SiO(R 2 SiO) m (R 1 RSiO) n SiR 2 R 1 and a number average molecular weight of
less than 20,000 are commercially available from sources such as Gelest Inc.
Preferred such materials have an alkenyl equivalent weight (as a result of the

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choice of m and n) of about 250 to about 10,000, more preferably, about 250 to
about 5000, and most preferably, about 250 to about 2000.

The high molecular weight polydiorganosiloxane component
(i.e., having a number average molecular weight of at least 20,000) is preferably
5 present in the adhesive compositions in an amount of at least about 50 weight
parts and no greater than about 95 weight parts, and the low molecular weight
polydiorganosiloxane component (i.e., having a number average molecular
weight of less than 20,000) is preferably present in the adhesive compositions in
an amount of at least about 5 weight parts and no greater than about 50 weight

1 0 parts, based on the total parts by weight of both the high and low molecular
weight polydiorganosiloxanes.

Suitable functional and nonfunctional MQ organopolysiloxane
resins are commercially available from sources^such as General Electric Co.,
Silicone Resins Division, Waterford, NY; PCR, Inc., Gainesville, FL; and

1 5 Rhone-Poulenc, Latex and Specialty Polymers, Rock Hill, SC. Examples are
disclosed in U.S. Pat. No. 5,082,706 (Tangney). Such resins are generally
supplied in organic solvent and may be employed in the adhesives of the present
invention as received. Typically, the amount of an MQ resin needed to achieve
desired levels of release and peel forces will depend on the total amount of the

20 high and low molecular weight polydiorganosiloxanes. The amounts of each of
the components of the adhesives of the present invention are preferably chosen
to provide the desired levels of peel and release forces described above.
Preferably, at least about 50 weight parts MQ resin and no greater than about 70
weight parts MQ resin is used to achieve the desired level of release force, when

25 the total weight parts (i.e. , parts by weight) of MQ resin plus

polydiorganosiloxanes (both high and low molecular weights) equals 100 parts.

Suitable organohydrogenpolysiloxane free of aliphatic
unsaturation having an average of at least 2 silicon-bonded hydrogen atoms in
each molecule are commercially available from sources such as Dow Corning,

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Midland, Ml and General Electric Silicones, Waterford, NY. Examples are
disclosed in U.S. Pat. No. 5,082,706 (Tangney).

Such silicone adhesives are prepared by addition-cure chemistry
and typically involve the use of a platinum or other Group VIIIB (i.e., Groups 8,

5 9, and 1 0) metal catalysts, typically, hydrosilation catalysts, to effect the curing
of the silicone adhesive. Reported advantages of addition-cured silicone
adhesives include reduced viscosity as compared to silicone adhesives prepared
via condensation chemistry, higher solids content, stable viscosity with respect
to time, and lower temperature cure. Methods of preparation are disclosed in

10 U.S. Pat. No. 5,082,706 (Tangney).

The adhesive composition may include other additives to adjust
for desired properties. For example, pigment may be added as colorant;
conductive compounds may be added to make an adhesive surface electrically
conductive or antistatic; antioxidants and bacteriastatic agents may be added;

1 5 light absorbers may be added to block certain wavelengths from passing through
the article; or inhibitors may be added to extend adhesive pot life, thus avoiding
premature gelation of the adhesive coating solution. Examples of such additives
are commercially available from various sources and are disclosed in U.S. Pat.
No. 5,082,706 (Tangney), as are desired amounts.

20 The adhesive composition can be applied to appropriate release

liners by a wide range of processes, including, solution coating, solution
spraying, etc., to make adhesive/release liner laminates, preferably at a coating
weight of about 0.2 grams/154.2 cm 2 to about 2.4 grams/154.2 cm 2 . Typically,
it is applied to a thermally resistant substrate, such as polyethylene terephthalate

25 coated with a fluorosilicone release material (such as that disclosed in U.S. Pat.
No. 5,082,706 and commercially available from Rexam Release, Bedford Park,
IL) to form an adhesive/release liner laminate. The adhesive transfer tape is
then laminated to a desired substrate, such as biaxially oriented polyethylene or
high density polyethylene, to form an adhesive tape, particularly a cover tape for

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an analytical receptacle. For evaluation of the release force of adhesives of the
present invention, a release liner that releases Dow Corning 7657 silicone
adhesive with a release force of less than about 1 0 N/dm is desired under the
conditions described herein.

5 Conventional cover tapes for microtiter plates include an

adhesive layer and a backing such as aluminum (Al) foil or polyethylene
terephthalate (PET). Aluminum foil backings are less desirable because they are
not transparent. PET tape backings have high mechanical strength and resist
puncture by all but the hardest, sharpest needles. A plastic pipette tip, for

1 0 example, requires high force to break through a very thin (approximately 1 mil
or 25 hn) PET backing.

Suitable backings for use in the cover tapes of the present
invention allow for puncture by needles or plastic sampling pipette tips, for
example. Such puncture sites may or may not reclose (i.e., reseal).

1 5 Alternatively, suitable backings that resist puncture can also be used.

Preferably, the backing will puncture without splitting. The backings can be
transparent, translucent, or opaque. Preferably, the backing is transparent
Transparency facilitates chemical analysis conducted by any one of several
methods of photometric analysis including, for example, ultraviolet, visible, and

20 fluorometric analysis.

The backing can include a wide range of substrate materials,
examples being polymer films such as polyethylene, polyethylene terephthalate
(PET), biaxially oriented polypropylene (BOPP), and metallocene-polymerized
poly(alpha-olefm) copolymers. These backing materials are generally resistant

25 to solvents commonly used in bioanalytical applications, as discussed above
with respect to the adhesives. They can resist puncture or not, although if they
are punctured, the puncture site does not reclose. Backings that allow for
reclosure of the puncture site are also possible.

WO 00/68336 PCT/US99/09945

The analytical receptacles to which the cover tapes can be applied
include a wide variety of articles. Preferably, the analytical receptacles include
at least one surface having one or more reservoirs therein. For example, a
suitable analytical receptacle to which a cover tape of the present invention can
5 be applied includes a microtiter plate, which is typically a plastic plate

containing a number of small flat-bottomed wells arranged in rows. Another
example is a tape that includes a substrate coated with a gel having .a plurality of
separate adjacent tracks thereon, as disclosed in U.S. Pat. No. 3,551,295 (Dyer).

Other analytical receptacles include microfluidic devices that

10 include a substrate and one or more channels therein. Such a structure, which
includes a body structure and at least one microscale channel disposed therein, is
disclosed in U.S. Pat. No. 5,842,787 (Kopf-Sill et al.). Yet another such
structure, which has a groove recessed in a flat substrate and defines a
microfluidic channel system, is disclosed in U.S. Pat. No. 5,443,890 (Ohman).

1 5 Yet another such structure, which includes a substrate with microstructures
fabricated therein, is disclosed in U.S. Pat. No. 5,804,022 (Kaltenbach et al.).

Another type of analytical receptacle includes a substantially
continuous polymeric strip formed to have wall portions defining a series of
identical reservoirs at predetermined, preferably, uniformly spaced, intervals

20 along its length, which reservoirs can have a variety of shapes. For example, the
reservoirs may comprise rectangular or generally "T or "T" shapes in the plane
of the strip, and may have flat or rounded bottoms as desired. Such receptacles
are disclosed, for example, in U.S. Pat. No. 4,883,642 (Bisconte). Others are
disclosed in U.S. Pat. No. 5,729,963 (Bird), which are designed for carrying

25 electrical parts, but can be modified for use as analytical receptacles.

These analytical receptacles can be formed from a variety of
materials, including, polyethylene, polystyrene, polypropylene, polycarbonate,
which can be carbon-black or Ti0 2 filled, transparent, translucent, or opaque.

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Experimental

Objects and advantages of this invention are further illustrated by the
following examples, but the particular materials and amounts thereof recited in these
5 examples, as well as other conditions and details, should not be construed to unduly
limit this invention.

Test Methods

10 peel Force Test: An 1-inch (2.54 cm) wide by 6-inch (15.24

cm) strip of each test adhesive tape sample was placed on a 20 mil (0.05 cm)
thick polypropylene plate. A 5-pound (2.27-kg) roller was then used to apply
the tape to the plate assembly to insure uniform contact. Subsequently, an Imass
Slip/Peel Tester model SP-102B-3M90 (Instruntentors Inc., Strongsville, OH)

15 was used to measure a 1 80° peel force between the silicone adhesive and the
polypropylene plate at a plate speed of 12 inches/minute (30.5 cm/minute),
according to ASTM D3330-D3330M-96. An average peel force per inch of
plate travel was registered on the tester. The test was repeated three times and
average value reported in Newtons per decimeter (N/dm).

20 Release Force Test: A tape laminate, 1 -inch (2.54 cm) wide by

6-inch (15.24 cm) long consisting of a tape backing, a layer of silicone adhesive,
and a fluorosilicone coated release liner (CLPET - 6J/000 available from Rexam
Release Corporation, Bedford Park, IL) was adhered to the clean glass base plate
of an Imass tester (Model SP-102B-3M90) with SCOTCH tape #41 1 (3M

25 Company, St. Paul, MN). The 1 80° release force between release liner and
silicone adhesive was measured at 30.5 cm/minute speed according to ASTM
D3330-D3330M-9 by pulling the backing/adhesive laminate from the release
liner. The average release force per inch of plate travel was registered on the

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tester and recorded. The experiment was repeated three times and average value
reported in N/dm.

Cross Contamination Test : In a polystyrene 96-well
microplate (available from Nalge International Corp, Naperville, IL)

5 alternating wells were filled with approximately 50 nl of a red colorant solution
(MERTH30LATE, supplied by Eli Lilly, approximately 1 : 50 dilution in water)
and the openings of the wells of the microplate were covered by the sample
adhesive cover tapes. The covered plate was subsequently inverted and shaken
several times. The wells in the plate were then visually observed to determine if

1 0 the indicator solution had migrated to an adjacent well.

Solvent Resistance Test: Sample adhesive tapes were adhered
to an aluminum plate with 6 wells, each well having a dimension of 0.6 cm
diameter and 0.6 cm depth. Prior to application^ the cover tape, DMSO (50
^1) was filled in each well and allowed to dwell for 24 hours in the tape-covered

1 5 wells. The tapes were subsequently inspected visually for evidence of swelling
or dissolution.

Extractables Test: Samples (4 cm x 5 cm) of each adhesive
cover tape were soaked in 5 ml of water or dimethyl sulfoxide (DMSO) for 24
hours. The sample adhesive tapes were also exposed to vapor phase contact

20 with the solvents in the wells of the sample adhesive tape-covered aluminum
plate described above for 7 days. The extracts were examined by gas
chromatography/mass spectroscopy (GC/MS) using a Finnigan "Magnum"
GC/ion trap mass spectrometer (available from Thermoquest Corporation., San
Jose, CA) equipped with a model ZB-5 column (30 meters in length, 0.25 mm

25 inner diameter, 0. 1 hn film (available from Phenomenex Torrence, CA), a 4-ml
Atas Optic 2 injector (available from Atas, Cambridge Cambridgeshire, United
Kingdom), and a Finnegan scanning electron impact detector available from
Thermoquest Corporation, San Jose, CA (electron impact scan range from 31
Daltons to 550 Daltons. The Atas injector was operated in a cold split, multi-

WO 00/68336 PCT/US99/09945

capillary liner mode with a helium carrier gas flow rate of about 1 ml/minute.

o o

The injection temperature was programmed at 30 C/second to 350 C, the oven

temperature was programmed to start from 50 C incrementally ramping at
20°C/minute to a final temperature of 320°C which was held for 2.5 minutes at
5 the end of the run and the transfer line temperature was set at 300°C. The
helium carrier gas pressure was programmed at 1 0 pounds per square inch (psi)
initially to 20 psi after 1 6 minutes.

Residual Adhesive on Probe Puncture Test: Sample tapes of
the noted compositions were adhered to a clear polystyrene 96-well nontreated

10 microplate (No. 3367 available from Coming Inc., Corning, NY). Each cover
tape was punctured five consecutive times at different locations with either a 22
gauge needle or a 10 ^1 plastic tip (available from Eppendorf Corp., Germany).
Subsequent to the puncture of each tape the barrel of the needles and the plastic
tips were visually inspected ( 1 Ox magnification) for evidence of adhesive

1 5 residue adhering to these puncturing devices .

Rate of Sample Evaporation Test: A PCR (polymerase chain
reaction) 96-well polypropylene Microamp Optical Plate, model N-80 10560
(available from Perkin Elmer Biosystems Co.,Norwalk, CT) was filled with 50
M-l of solvent in each well. A test sample of an adhesive cover tape was then

20 adhered to the Microamp optical plate covering the well openings. Weight loss
due to evaporation of the water was monitored gravimetrically as a function of

time at room temperature (approximately 24 C) over a period of 24 hours, to
detect any change.

Examples 1-25

Materials

_ Corning 7657 (available from Dow Corning Corporation,

30 Midland, MI) silicone adhesive containing 56.5 parts silicone solids (44 wt %

WO 00/68336 PCT/US99/09945

vinyldimethylsiloxane terminated polydimethylsiloxane with molecular weight
approximately 500,000 and 56 wt % nonreactive MQ tackifying resin) with
xylene as the diluent. Additional amounts of the same nonreactive MQ
tackifying resin were added by the manufacturer to the Dow Corning 7657

5 adhesive to provide adhesive solutions 7657-2, 7657-4, 7657-6, and 7657-8
containing 58, 60, 62, and 64 wt % MQ respectively. Toluene (available from
Worum Chemical Company, St. Paul, MN) was added to each formulation to
provide the adhesive at 40 wt % solids content for ease of coating.

Dow Corning (Dow Coming Corporation, Midland, MI) SYL-

1 0 OFF 76 1 5 release modifier (designated as 76 1 5) containing approximately 40 wt
% dimethylvinylated and trimethylated silica; 57 wt % dimethylsiloxane,
dimethyl vinyl terminated with a degree of polymerization of 25; 1 wt %
tetra(trimethylsiloxy) silane; 1 wt % of a Dow Corning proprietary ester; and a
platinum-containing catalyst.

1 5 Dow Coming S YL-OFF 7678 crosslinker (designated as 7678)

containing dimethylsiloxane methylhydrogensiloxane copolymer.

Dow Coming SYL-OFF 4000 catalyst (designated as 4000)
containing dimethyl vinyl terminated polydimethylsiloxane,
tetramethyldivinyldisiloxane, and a platinum siloxane complex.

Formulations

Adhesive Composition A: 250 parts of Dow Corning 7657
silicone base adhesive at 40% solids in toluene/xylene, and 1 part of SYL-OFF
4000 catalyst.

25 Adhesive Composition B: 250 parts of Dow Corning 7657-2

silicone base adhesive at 40% solids in toluene/xylene, and 1 part of SYL-OFF
4000 catalyst.

WO 00/68336 PCT/US99/09945

Adhesive Composition C: 250 parts of Dow Corning 7657-4
silicone base adhesive at 40% solids in toluene/xylene, and 1 part of SYL-OFF
4000 catalyst.

Adhesive Composition D: 250 parts of Dow Corning 7657-6
5 silicone base adhesive at 40% solids in toluene/xylene, and 1 part of SYL-OFF
4000 catalyst.

Adhesive Composition E: 250 parts of Dow Corning 7657-8
silicone base adhesive at 40% solids in toluene/xylene, and 1 part of SYL-OFF
4000 catalyst.

10 Modifier 761 5: 93 parts of SYL-OFF 761 5 release modifier and

7 parts of SYL-OFF 7678 crosslinker.

The silicone adhesives were prepared according to the
formulations listed above in the proportions disclosed in Tables 1-5. Adhesive

1 5 Compositions A-E were prepared by combining the above-listed components
and mixing two to four hours on a roller at room temperature. Modifier 76 1 5
was added to the Adhesive Compositions A-E and mixed on a roller at room
temperature for an additional two to four hours to obtain homogeneous adhesive
solutions for coating.

20 The resulting adhesive solution was applied on a release liner

(CLPET-6J/000 transfer liner from Rexam Release Corp., Beford Park, EL)
using a knife coater at 6-7 mils orifice, dried and cured by passing through a
three-zone oven, at a rate of 3 feet/minute (0.914 meters/minute). The oven

o . o

zone temperatures and residence times were 71 C for 3 minutes, 82 C for 3
25 minutes, and 82°C for 6 minutes, respectively. A balance was then used to
confirm an adhesive coating weight of approximately 0.768-0.896 grams per
154.8 cm square.

The silicone adhesive/release liner laminate was then laminated to
an embossed tape backing, 0.01 cm thick, corona-treated ethylene/propylene

WO 00/68336 PCT/US99/09945

copolymer (PP-PE) film (BPI Code #26379-3, Bloomer Plastics Inc., Bloomer,
WI) by passing the adhesive/release liner laminate and embossed tape backing
through a nip roll.

The peel force test and release force test were measured on each
5 of the prepared samples and reported in Tables 1 -5. The results suggest that
there is little effect on the peel forces of the silicone tapes when 0-20 parts of
silicone modifier were added to the silicone adhesive. Surprisingly, the results
show that addition of silicone modifier serves to decrease release force without
adversely affecting peel adhesion.

Table 1

Adhesive Composition A with 0, 5, 10, 15, and 20 parts of Modifier 7615

Example

Modifier 7615

Peel Force

Release Force

(N/dm)

Opart

24.6

7.1

5 parts

22.0

6.7

10 parts

21.2

4.4

15 parts

21.5

2.1

20 parts

22.5

1.5

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Table 2

Adhesive Composition B with 0, 5, 10, 1 5, and 20 parts of Modifier 7615

Example

Modifier 7615

Peel Force

Release Force

(N/dm)

Opart

21.5

.4-5

5 parts

23.8

2.4

10 parts

24.5

1.0

15 parts

23.1

1.2

20 parts

25.1

1.0

Table 3

Adhesive Composition C with 0, 5, 10, 15, and 20 parts of Modifier 7615

Example

Modifier 7615

Peel Force

Release Force

(N/dm)

Opart

25.2

2.8

5 parts

23.5

2.9

10 parts

27.8

0.4

15 parts

27.4

0.2

20 parts

28.2

0.2

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Table 4

Adhesive Composition D with 0, 5, 10, 15, and 20 parts of Modifier 7615

Example

Modifier 7615

Peel Force

Release Force

(N/dm)

Opart

20.9

0.4

5 parts

22.3

0.3

10 parts

29.8

0.2

15 parts

30.3

0.2

20 parts

26.7 j

0.2

Table 5

Adhesive Composition E with 0, 5, 10, 15, and 20 parts of Modifier 7615

Example

Modifier 76 15

Peel Force

Release Force

(N/dm)

Opart

4.8

0.08

5 parts

8.7

0.09

10 parts

4.2

0.03

15 parts

7.0

0.04

20 parts

8.5

0.05

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Examples 26-47 and Comparative Examples C1-C5
5 Materials

Dow Corning 7657 silicone adhesive diluted to 40 wt % solids

with toluene.

Vinyl Fluid A: a vinyl dimethylsiloxane terminated
polydiemthylsiloxane fluid with degree of polymerization of 24.
10 Vinyl Fluid B: a vinyldimethylsiloxane terminated

polydiemthylsiloxane fluid with degree of polymerization of 67.

Vinyl Fluid C: a vinyldimethylsiloxane terminated
polydiemthylsiloxane fluid with degree of polymerization of 101.

Vinyl Fluid D: a vinyldimethylsiloxane terminated
1 5 polydiemthylsiloxane fluid with degree of polymerization of 1 67.

Vinyl Fluid E: a vinyldimethylsiloxane terminated
polydiemthylsiloxane fluid with degree of polymerization of 245.

Vinyl Fluid F: a vinyldimethylsiloxane terminated
polydiemthylsiloxane fluid with degree of polymerization of 459.
20 MQ resin solution: 63.4% nonreactive MQ resin (used in Dow

Coming 7657 silicone adhesive) in xylene, provided by Dow Coming.

2EHHM: 2-ethylhexylhydrogen maleate was prepared by
reacting one mole of maleic anhydride with one mole of 2-ethyl-l-hexanol.

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Formulations

Master batches of low molecular weight vinyl-substituted
polydiorganosiloxanes ("vinyl-fluid" having varying degrees of polymerization)
were prepared according to the following formulations.

Master
Batch

Vinyl
Fluid

Vinyl Fluid
Amount (g)

MQ resin
solution

(g)

SYL-OFF
7678
crosslinker (g)

2EHHM (g)

21.0

46.4

2.1

0.17

19.1

39.8

0.72

0.15

19.3

39.8

0.49

0.15

19.5

39.8

0.30

0.15

19.6

39.8

0.21

0.15

19.7

39.8

0.11 "

0.15

For each of the following examples, the proper amount of each
Master Batch as indicated in Tables 6-1 1 was mixed with 50 grams of the 40%

1 0 solids Dow Coming 7657 and 0.2 gm of SYL-OFF 4000. A tumbling roller was
used for 2-4 houre to insure uniform mixing prior to coating.

The resulting adhesive solutions were applied on a release liner
(CLPET-6 J/000 transfer liner from Rexam Release, Bedford Park, IL) and
coated, dried, and cured as in Examples 1-25, with the exception that oven zones

15 1, 2, and 3 were set at temperatures of 125°C, 149°C, and 149°C, respectively.
The adhesive/release liner laminate was then laminated on a tape backing, BOPP
(biaxially oriented polypropylene film) available from 3M Company, St. Paul,
MN under the trade name SCOTCHPRO having a thickness of 3 1 l%i (1 .2 mils).
The BOPP tape backing was corona-treated to enhance bonding of the silicone

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adhesive. The laminate of backing with adhesive and liner was constructed by
passing the transfer tape and backing through a nip roll.

The peel force and release force of the tapes were measured
utilizing the respective tests described above and reported in Tables 6-11. The

5 release force for Example CI , which is the equivalent formulation to that of
Example 1, has increased dramatically. This suggests that the fluorosilicone
release liner (due to lot to lot variation) used for Tables 6-1 1 was less effective
as compared with those in Tables 1-5. Nevertheless, the results in Examples 1-
25 and Examples 26-47 confirm that adding low molecular weight silicone vinyl

1 0 fluid (with or without reactive MQ resins) in the silicone adhesive formulations
has a significant effect on lowering the release force of silicone adhesives from
the release liner without adversely affecting peel adhesion. The data also
suggest that a broad range of low molecular weight vinyl functional silicone
fluids may be added in the silicone base adhesive with little- effect on the peel

1 5 forces of the silicone tapes.

Table 6

Coating Formulation with Vinyl Fluid A (DP = 24)

Example

Master
Batch

Master
Batch
Amount (g)

Amount of Vinyl
Fluid A in Master
Batch A (g)

Peel Force
from PP
(N/dm)

Release
Force
(N/dm)

0.000

37.0

34.6

2.65

0.800

37.7

34.5

5.31

1.600

34.4

16.6

7.96

2.401

29.7

2.9

10.61

3.201

28.6

0.9

13.27

4.001

22.6

0.2

15.92

4.801

13.9

0.0

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Table 7

5 Coating Formulation with Vinyl Fluid B (DP = 67)

Example

Master

Amount of Vinyl

Peel Force

Release Force

Batch

Fluid B in Master

fromPP

(N/dm)

Amount (g)

Batch B (g)

(N/dm)

7.96

2.543

28.9

16.6

10.61

3.391

25.9

11.4

13.27

4.239

22.5

8.5

15.92

5.087

21.2

6.7

10 Table 8

Coating Formulation with Vinyl Fluid C (DP = 101)

Example

Master
Batch

Master
Batch
Amount (g)

Amount of Vinyl
Fluid C in Master
Batch C (g)

Peel Force
fromPP
(N/dm)

Release Force
(N/dm)

7.96

2.574

23.7

24.9

10.61

3.432

27.4

16.8

13.27

4.291

24.8

12.8

15.92

5.149

26.3

10.8

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Table 9

Coating Formulation with Vinyl Fluid D (DP = 167)

Example

Master
Batch

Master
Batch
Amount (g)

Amount of Vinyl
Fluid D in Master
Batch D (g)

Peel Force
from PP
(N/dm)

Release Force
(N/dm)

7.96

2.599

30.4

27.2

10.61

3.466

27.9

23.5

13.27

4.332

26.5

18.2

15.92

5.199

23.3

16.5

Table 10

Coating Formulation with Vinyl Fluid B (DP = 245)

Example

Master
Batch

Master
Batch
Amount (g)

Amount of Vinyl
Fluid E in Master
Batch E (g)

Peel Force
fromPP
(N/dm)

Release Force
(N/dm)

7.96

2.612

28.6

31.5

10.61

3.483

27.1

26.6

13.27

4.353

26.3

24.4

15.92

5.224

26.1

21.6

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Table 1 1

Coating Formulation with Vinyl Fluid F (DP = 459)

Example

Master
Batch

Master
Batch
Amount (g)

Amount of Vinyl
Fluid F in Master
Batch F (g)

Peel Force
fromPP
(N/dm)

Release Force
(N/dm)

7.96

2.625

31.8

37.0

10.61

3.500

30.7

34.3

13.27

4.375

28.8

35.3

15.92

5.250

28.8

30.3

5 Examples 48-49 and Comparatives C6-C11

The silicone adhesive composition of Example 13 on a release
liner (CLPET-6J/000 transfer liner from Rexam Release Corporation, Bedford
Park, IL) was laminated with the following backings.

Example 48 used an embossed high density polyethylene

1 0 designated as PE (Product No. B 1 00NA from Bloomer Plastics, Bloomer, WI) .
The embossed film thickness was 101.6 (4 mils).

Example 49 used a biaxially-oriented polypropylene having a
thickness of 30.5 l^m (1.2 mil) and designated as BOPP available by the trade
designation SCOTCHPRO from 3M Company, St. Paul, MN.

15 in a polystyrene 96-well microplate (available from Nalge Nunc

International Corp, Naperville, IL) alternating wells were filled with
approximately 50 jal of a red colorant solution (MERTHIOLATE, supplied by
Eli Lily, approximately 1:50 dilution in water) and the openings of the wells of
the microplate were covered by the sample adhesive cover tapes of Examples 48

20 and 49. The covered plate was subsequently inverted and shaken several times.

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The wells in the plate were then visually observed that showed no indicator
solution had migrated to an adjacent well.

Samples of the tapes of Examples 48 and 49 were applied over a
96-well polypropylene microplate (Cat. No. 3364 available from Corning Inc.,
5 Corning , NY), with DMSO in the micro-wells, for 24 hours under ambient
conditions. There was no noticeable change of adhesion of the cover tapes of
the invention to the polypropylene plate. However, Comparative Example C6
consisting of anitrile rubber adhesive tape labeled (Product Number SJ3101
available from Minnesota Mining and Manufacturing Co., St. Paul, MN) and

10 Comparative Example C7 consisting of a PET backing adhesive tape

(THINSEAL tape available from PGC Scientifics, Gaithersberg, MD) each
exhibited total loss of adhesion when exposed to the same test conditions, as
shown in Table 12. x

These same four cover tapes were adhered to'a clear polystyrene

1 5 96-well nontreated microplate (No. 3367 available from Corning Inc., Corning,
NY). Each cover tape was punctured five consecutive times at different
locations with a 22 gauge needle. Subsequent to the puncture of each tape the
barrel of the needles were visually inspected (lOx magnification) for evidence of
adhesive residue adhering to these puncturing devices. These results are shown

20 in Table 12.

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Table 12

DMSO Resistance of Silicone Tapes and Comparative Tapes

Example

Tape |
Backing

Adhesion in DMSO
(24 hours)

Residue 22 G Needle

HDPE

Ok*

No residue visible

BOPP

Ok*

No residue visible

SJ3101

Swollen, lost
adhesion

No residue visible

THINSEAL

Swollen, lost
adhesion

No residue visible

*no noticeable change of adhesion.

Table 13 reports the extraction data obtained in the Extractables
Test utilizing the GC/MS conditions listed above with several common solvents
utilized within a typical bioanalytical lab when preparing sample that would be
introduced to a multi-well aluminum plate and covered. Samples of the tapes

10 were placed in DMSO, water and 80/20 acetonitrile/water mixture for 24 hours.
Any extractable material was analyzed with GC/MS. The results indicated that
no material was extracted from any of these tapes.

Comparative 8 was Corning cover tape (product number 3095)
commercially available from Corning Corp., Coming, NY. Comparative 9 was

15 product number 62367 cover tape available from Zymark Corp., Hopkinton,
MA. Comparative 10 was Costar product number 6569 cover tape available
from Corning Costar Corp., Acton, MA. Comparative 1 1 was Ultra-Plate cover
tape available from Sagian Corporation, Indianapolis, IN. Each of these cover
tape samples were used as received. The results demonstrate a significant value

20 of the present invention is the ability of cover tapes of the present invention to
resist commonly used solvents in bioanalytical applications.

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Table 13

Tape Extraction Data by GC/MS with several common solvents for 24 hours

example

Tane/PSA

DMSO
(V-olcrrr total

extractants)

80/20
AN*/H 2 0
(^g/cm 2 total
extractants)

Water
(^e/cm 2 total
extractants)

Silicone

N.T.

0-1

Comp. 8

Corning 3095

-5,000**

N.T.

Comp. 9

Zymark P/N
62367

-5,000**

N.T.

Comp. 10

Costar 6569

N.T.

Comp. 1 1

Ultra-Plate

-5,000**

N.T.

N.T. = not tested.

5 * AN=acetonitrile.

♦♦Indicates that sample fully dissolved in extractant and exceeded the
measurable range of the instrument. Values were calculated by mass balance
before and after extraction.

10 Evaporation Rates of Example 42 and Comp. 12

Table 14 compares the evaporation rate of water in 24 hours for
cover tapes applied to a Perkin Elmer PCR 96-well plate. The tapes consisted oif
the silicone cover tape of Example 42 having a peel adhesion around 27 N/dm,
and Comparative Example 12, CYCLE SEAL cover tape (by Robbins Scientific
1 5 Corp. , Sunnyvale, CA) having a peel adhesion less than 5 N/dm. The data show
that the silicone tape of the present invention provides a superior seal against the
plate well as compared to a commercial cover tape having low peel adhesion.

WO 00/68336 PCT/US99/09945

Table 14

Evaporation Rates of Water in 24 Hours on a Perkin Elmer PCR 96-Well Plates

Example

Samples

Evaporation/24 hr

BOPP with silicone PSA

-3%

Comp 12

Robbins (CYCLESEAL)
30 mils Thick, low peel

-25%

Evaporation Rates of Example 50 and Comp. 13-15

Example 50 utilized the adhesive of Example 42 and a 3-layer
(A/B/A) coextruded film for the adhesive tape backing, where outerlayer A

1 0 (thickness = 7 microns) was FINA polypropylene #3 825 (available from FINA
Oil & Chemical Co., Dallas, TX) and B is KRATON G1657 (available from
Shell Chemical, Houston, TX) (thickness = 63 microns). The films were
prepared on a coextrusion line using a Cloeren (Orange, Texas) ABBBC
feedblock. The B Layer (elastic core) was split into three layers in the

1 5 feedblock, recombined and sandwiched between the two skin layers to form the
three-layer coextruded film. The A Layer (skin 1) was cast against a rubber nip
roll. The C Layer (skin 2) was cast against a patterned steel chill roll. Extruder
A (skin 1) was a 2.5-inch single screw (24: 1 L/D) manufactured by David
Standard Corporation (Pawcatuck, CT). Extruder B (elastic core) was a 2.5-inch

20 single screw (32: 1) manufactured by Extruders Inc. and Extruder C (skin 2) was
a 1.5-inch single screw (24: 1 L/D) manufactured by David Standard.

Comparative Examples 13 and 14 were commercially available
adhesive tapes. Aluminum adhesive tape (Comp. 13, from Marsh Biomedical
Products, Inc., Rochester, NY) and a PET adhesive tape (Comp. 14, trade name

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THINSEAL from PGC Scientifics, Gaithersburg, MD) were used for
comparison. Comparative 15 was an open will (without a cover tape).

After removing the release liner from the tapes of Example 50
and Comparatives 13 and 14, they were used as cover tapes to seal a 96-well
5 polypropylene Microamp Optical Plate, model N-80 1 0560 (available from
Perkin Elmer Biosystems Co., Norwalk, CT) filled with 50 H- 1 of water in each
well.

In a first experiment, the adhesive cover taped microplate of
Example 50 was inverted with the adhesive in contact with the openings of the

1 0 microwells. The tape of Example 50 was then pierced several times using an 18-
gauge stainless steel needle of a hypodermic syringe to facilitate removal of
water from selected micro-wells. After withdrawing the needle, and inverting
the microplate, there was no visual evidence of leakage from any micro-well
covered with the tape of Example 50. It should also be noted that after

1 5 completing the penetration test, there was no evidence of adhesive residue on the
surface of the probe used to pierce the cover tape of Example 50.

In a second experiment, the cover tapes of each of Examples 50
gnd Comparatives 13 and 14 were pierced with a 22-gauge needle at room
conditions. Table 15 shows the evaporation rates of the pierced cover tapes of

20 this second experiment applied to the surface of a 96-well polypropylene
Microamp Optical Plate, model N-8010560 (available from Perkin Elmer
Biosystems Co., Norwalk, CT) filled with representee solvents. The solvents
covered by the tapes were acetonitrile/water (84: 1 6 by wt), water, and DMSO.
For Example 50, loss by evaporation was minimal and no leakage was detected

25 after shaking the plate vigorously, as compared to Comparatives 13 and 14. The
negative value for Example 50 with DMSO appears to be due to sorption of
moisture by DMSO at room condition. Comparative 15 showed the evaporation
rate of the solvent without a cover tape.

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Table 15

Effect of A Septum Tape Backing on the Evaporation Rates of Some
Commonly Used Solvents

Example

Solvents

Evaporation/hr

Acetonitrile: Water (84: 16 by wt).

0.12%

Water

0.02%

DMSO

^0.02%

Comp 13

Acetonitrile: Water (84: 16 by wt).

0.75%

Comp 14

Acetonitrile: Water (84: 16 by wt).

1.10%

Comp 15*

Acetonitrile: Water (84: 16 by wt).

29%

* No cover tape

Peel Force of Cover Tapes from Nitrile Rubber

Peel force of adhesive tapes from a nitrile rubber surface (type:
N-DEX 60005 PFM powders free, Best Manufacturing Co., Menio, GA) were

1 0 measured using the Peel Force Test described above, except a portion of a nitrile
rubber glove was adhered to the polypropylene plate with SCOTCH tape #41 1
(3M Companty, St. Paul, MN). The data is shown in Table 16 for the cover
tapes of Examples 1 1-1 5 and Comparative 14. The silicone tapes in this
invention have very low peel adhesion to the commonly used rubber gloves.

1 5 Furthermore, the silicone tapes have very low tack when touched with fingers or
rubber gloves.

WO 00/68336

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Table 16

Peel Adhesion of Tapes on Nitrile Rubber Glove Surfaces

Example

Peel Adhesion (N/dm)

Example 1 1

2.2

Example 12

1.7

Example 13

Example 14

Example 15

Comp. 14

19.0

10 The complete disclosures of the patents, patent documents, and

publications cited herein are incorporated by reference in their entirety as if each
were individually incorporated. Various modifications and alterations to this
invention will become apparent to those skilled in the art without departing from
the scope and spirit of this invention. It should be understood that this invention

1 5 is not intended to be unduly limited by the illustrative embodiments and
examples set forth herein and that such examples and embodiments are
presented by way of example only with the scope of the invention intended to be
limited only by the claims set forth herein as follows.

WHAT IS CLAIMED IS:

An adhesive prepared from components comprising:

(a) a polydiorganosiloxane having the general formula
R'R.SiOCR.SiOXSiR^.R 1 and a number average molecular weight of
at least 20,000, wherein each R is independently a monovalent
hydrocarbon group, each R 1 is independently an alkenyl group, and n
is an integer,

(b) a polydiorganosiloxane having the general formula
R^sSiOCRsSiO^R^SiO^SiRnR 1 and a number average molecular
weight of less than 20,000, wherein each R and R 1 is independently a
monovalent hydrocarbon group, at least two R 1 groups are alkenyl
groups, and m and n are integers the sum of which provide an alkenyl
equivalent weight of about 250 to a^out 1 0,000;

(c) an organopolysiloxane MQ resin which contains (R 2 ) 3 Si0 1/2 units and
Si0 2 units in a molar ratio in the range of 0.6: 1 to 1 : 1 , wherein each
R 2 is independently selected from the group of alkyl groups, alkenyl
groups, or hydroxyl groups, wherein at least 95 mole percent of all
R 2 groups are methyl groups;

(d) an organohydrogenpolysiloxane free of aliphatic unsaturation having
an average of at least 2 silicon-bonded hydrogen atoms in each
molecule, in a quantity sufficient to provide from 1 to 40 silicon-
bonded hydrogen atoms per alkenyl group in components (a) through
(c); and

(e) a Group VIIIB-containing catalyst in a quantity sufficient to provide
0.1 to 1,000 weight parts Group VIIIB metal for each one million
weight parts of the combined quantity of components (a) through (d).

The adhesive of claim 1 wherein the organopolysiloxane MQ resin
includes both nonfunctional and functional MQ resins.

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3. The adhesive of claim 2 wherein the functional MQ resin includes
alkenyl groups.

5 4. The adhesive of claim 1 when disposed on a fluorosilicone-coated
polyethylene terephthalate release liner and a propylene/ethylene
copolymer backing at a coating weight of 0.8 grams/1 54.8 cm 2 to form a
laminate, and when adhered to a glass plate, displays a 180° release force
of no greater than about 20 N/dm when measured at 30.5 cm/minute and

1 0 room temperature.

5. The adhesive of claim 4 which displays a release force of no greater than
about 15 N/dm. x

1 5 6. The adhesive of claim 5 which displays a release force of no greater than
about 10 N/dm.

7. The adhesive of claim 6 which displays a release force of no greater than
about 5 N/dm.

8. The adhesive of claim 1 when disposed on a propylene/ethylene
copolymer backing at a coating weight of 0.8 grams/154.8 cm 2 and

adhered to a polypropylene plate displays a 1 80 peel force of at least
about 5 N/dm when measured at 30.5 cm/minute and room temperature.

9. The adhesive of claim 1 which is a pressure sensitive adhesive.

10. An adhesive article comprising a substrate having disposed on at least
one major surface the silicone-based adhesive of claim 1 .

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PCT7US99/09945

1 1 . The adhesive article of claim 1 0 wherein the organopolysiloxane MQ
resin includes both nonfunctional and functional MQ resins

5 12. The adhesive article of claim 10 further comprising a release liner
disposed on the adhesive.

13. The adhesive article of claim 10 wherein the adhesive when disposed on
a fluorosilicone-coated polyethylene terephthalate release liner and a
1 0 propylene/ethylene copolymer backing at a coating weight of 0.8

grams/154.8 cm 2 to form a laminate, and when adhered to a glass plate,
displays a 1 80° release force of no greater than about 20 N/dm when
measured at 30.5 cm/minute and room temperature.

15 14. The adhesive article of claim 13 wherein the adhesive displays a release
force of no greater than about 5 N/dm.

15. The adhesive article of claim 10 wherein the adhesive when disposed on
a propylene/ethylene copolymer backing at a coating weight of 0.8

20 grams/154.8 cm 2 and adhered to a polypropylene plate displays a 180°

peel force of at least about 5 N/dm when measured at 30.5 cm/minute
and room temperature.

16. The adhesive article of claim 1 0 wherein the backing comprises a
25 puncturable material.

17. The adhesive article of claim 10 wherein the adhesive is a pressure
sensitive adhesive.

WO 00/68336

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18. An analytical receptacle comprising a surface and a cover tape adhered to
the surface; wherein the cover tape comprises a backing and the adhesive
of claim 1 disposed on at least one major surface of the backing and in
contact with the receptacle surface.

1 9. The analytical receptacle of claim 1 8 further comprising one or more
reservoirs in the form of a well or channel.

20. The analytical receptacle of claim 18 wherein the analytical receptacle
10 comprises a substantially continuous tape.

21. The analytical receptacle of claim 18 wherein the adhesive is a pressure
sensitive adhesive. ^

15 22. The analytical receptacle of claim 1 8 wherein the adhesive when

disposed on a fluorosilicone-coated polyethylene terephthalate release
liner and a propylene/ethylene copolymer backing at a coating weight of
0.8 grams/1 54.8 cm 2 to form a laminate, and when adhered to a glass
plate, displays a 1 80° release force of no greater than about 20 N/dm

20 when measured at 30.5 cm/minute and room temperature.

23. The analytical receptacle of claim 22 wherein the adhesive displays a
release force of no greater than about 5 N/dm.

25 24. The analytical receptacle of claim 1 8 wherein the adhesive when

disposed on a propylene/ethylene copolymer backing at a coating weight
of 0.8 grams/154.8 cm 2 and adhered to a polypropylene plate displays a
1 80° peel force of at least about 5 N/dm when measured at 30.5
cm/minute and room temperature.

WO 00/68336 PCT/US99/09945

25. The analytical receptacle of claim 1 8 further comprising one or more
reservoirs including a liquid therein during use.

5 26. The analytical receptacle of claim 25 wherein the liquid comprises
dimethyl sulfoxide, water, acetonitrile/water, methanol, ethanol, or
mixtures thereof.

27. The analytical receptacle of claim 1 8 comprising a microtiter plate.

28. The analytical receptacle of claim 18 comprising a microfluidic device
comprising a substrate and one or more channels therein.

29. The analytical receptacle of claim 18 comprising a substantially

1 5 continuous polymeric strip comprising a plurality of reservoirs at

predetermined intervals along its length.

30. The analytical receptacle of claim 29 wherein the reservoirs are
uniformly spaced.

An analytical receptacle comprising a surface comprising polypropylene,
polystyrene, or combination thereof, and a cover tape adhered to the
surface; wherein the cover tape comprises a backing and an adhesive
disposed on at least one major surface of the backing and in contact with
the receptacle surface, wherein the adhesive is prepared from
components comprising:

(a) a polydiorganosiloxane having the general formula
R 1 R 2 SiO(R 2 SiO) n SiR 2 R I wherein each R is independently a
monovalent hydrocarbon group, each R 1 is independently an alkenyl
group and n is an integer,

(b) an organopolysiloxane MQ resin which contains (R 2 ) 3 Si0 1/2 units and
Si0 2 units in a molar ratio in the ran^e of 0.6: 1 to 1 : 1, wherein each
R 2 is independently selected from the group of alkyl groups, alkenyl
groups, or hydroxyl groups, wherein at least 95 mole percent of all
R 2 groups are methyl groups;

(c) an organohydrogenpolysiloxane free of aliphatic unsaturation having
an average of at least 2 silicon-bonded hydrogen atoms in each
molecule, in a quantity sufficient to provide from 1 to 40 silicon-
bonded hydrogen atoms per alkenyl group in component (a) and
component (b) if present; and

(d) a Group VHIB-containing catalyst in a quantity sufficient to provide
0. 1 to 1 ,000 weight parts Group VIIIB metal for each one million
weight parts of the combined quantity of components (a) through (c).

An analytical receptacle comprising a surface and a cover tape adhered to
the surface; wherein the cover tape comprises a backing and an adhesive
disposed on at least one major surface of the backing and in contact with

WO 00/68336

PCT/US99/09945

the receptacle surface, wherein the adhesive is prepared from
components comprising:

(e) a polydiorganosiloxane having the general formula
R l R 2 SiO(R 2 SiO) n SiR 2 R 1 wherein each R is independently a

5 monovalent hydrocarbon group, each R 1 is independently an alkenyl

group and n is an integer;

(f) an organopolysiloxane MQ resin which contains (R 2 ) 3 Si0 1/2 units and
Si0 2 units in a molar ratio in the range of 0.6; 1 to 1 : 1, wherein each
R 2 is independently selected from the group of alkyl groups, alkenyl

10 groups, or hydroxyl groups, wherein at least 95 mole percent of all

R 2 groups are methyl groups;

(g) an organohydrogenpolysiloxane free of aliphatic unsaturation having
an average of at least 2 silicon-bondp d hydrogen atoms in each
molecule, in a quantity sufficient to provide from 1 to 40 silicon-

15 bonded hydrogen atoms per alkenyl group in component (a) and

component (b) if present; and

(h) a Group VIIIB-containing catalyst in a quantity sufficient to provide
0. 1 to 1 ,000 weight parts Group VIHB metal for each one million
weight parts of the combined quantity of components (a) through (c);

20 wherein the adhesive when disposed on a fluorosilicone-coated polyethylene
terephthalate release liner and a propylene/ethylene copolymer backing at a
coating weight of 0.8 grams/ 154.8 cm 2 to form a laminate, and when adhered to
a glass plate, displays a 180° release force of no greater than about 20 N/dm
when measured at 30.5 cm/minute and room temperature.

A method of making an adhesive comprising:
preparing a composition comprising:

(a) a polydiorganosiloxane having the general formula
R 1 R 2 SiO(R 2 SiO) n SiR 2 R 1 and a number average molecular weight of
at least 20,000, wherein each R is independently a monovalent
hydrocarbon group, each R 1 is independently an alkenyl group, and n
is an integer,

(b) a polydiorganosiloxane having the general formula
R 1 R 2 SiO(R2SiO) m (R l R 2 SiO) n SiR 2 R 1 and a number average molecular
weight of less than 20,000, wherein each R and R l is independently a
monovalent hydrocarbon group, at least two R 1 groups are alkenyl
groups, and m and n are integers the sum of which provide an alkenyl
equivalent weight of about 250 to about 10,000;'

(c) an organopolysiloxane MQ resin which contains (R^SiO,^ units and
Si0 2 units in a molar ratio in the range of 0.6: 1 to 1 : 1 , wherein each
R 2 is independently selected from the group of alkyl groups, alkenyl
groups, or hydroxyl groups, wherein at least 95 mole percent of all
R 2 groups are methyl groups;

(e) a Group VHIB-containing catalyst in a quantity sufficient to provide
0. 1 to 1 ,000 weight parts Group VIIIB metal for each one million
weight parts of the combined quantity of components (a) through (d);
and

thermally curing the composition.

WO 00/68336

PCT/US99/09945

34. A method of sealing an analytical receptacle comprising applying a cover
tape comprising a backing and the adhesive of claim 1 disposed on at
least one major surface thereof

INTERNATIONAL SEARCH REPORT

interr lai Application No

PCT/US 99/09945

A. CLASSIFICATION OF SUBJECT MATTER

IPC 7 C09J183/07 B65B9/04

According to International Patent Classification (IPC) or to both national classification and IPC

B. FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)

IPC 7 C09J B65B

Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched

Electronic data base consulted during the international search (name of data base and, where practical, search terms used)

C. DOCUMENTS CONSIDERED TO BE RELEVANT

Category •

Citation of document with Indication, where appropriate, of the relevant passages

Relevant to claim No.

EP 0 581 539 A (GEN ELECTRIC)
2 February 1994 (1994-02-02)
claims 1,3,4,9

page 5, line 31 -page 6, line 9

1-3

US 5 082 706 A (TANGNEY THOMAS J)
21 January 1992 (1992-01-21)
cited 1n the application
claim 1

US 5 721 136 A (TITC0MB PAUL ET
24 February 1998 (1998-02-24)
cited in the application
claims 1-14

AL)

•/-

j x| Further documents are Osted in the continuation of box C.

Patent family members are listed in annex

* Special categories of cited documents :

"A" document defining the general state of the art which i3 not

considered to be of particular relevance
"E" earlier document but published on or after the international

filing date

V document which may throw doubts on priority claim(s) or
which is cited to establish the publication date of another
citation or other special reason (as specified)

"O" document referring to an oral disclosure, use. exhibition or
other means

"P" document published prior to the international filing date but
later than the priority date claimed

T later document published after the International filing date
or priority date and not in conflict with the application but
cited to understand the principle or theory underlying the
invention

"X* document of particular relevance: the claimed invention
cannot be considered novel or cannot be considered to
involve an inventive step when the document is taken alone

*Y' document of particular relevance; the claimed Invention
cannot be considered to involve an inventive step when the
document is combined with one or more other such docu-
ments, such combination being obvious to a person skilled i
in the art j
document member of the same patent family

Date of the actual completion of the international search

Date of mailing of the international search report

5 January 2000

18/01/2000

Name and mailing address of the ISA

European Patent Office. P.B. 5818 Patentlaan 2
NL-2280 HVRijswijk
Tel. (+31-70) 340-2040. Tx. 31 661 epo nl,
Fax: (+31-70) 340-3016

Authorized officer

Depijper, R

Form POT/lSA/21 0 (second sheet) ( JJy 1 992)

page 1 of 2

INTERNATIONAL SEARCH REPORT

page 2 of 2

INTERNATIONAL SEARCH REPORT

Information on patent family members

Interr nal Application No

PCT/US 99/09945

Patent document
cited in search report

Publication
date

Patent family
member(s)

Publication
date

EP 0581539

02-02-1994

2101708 A

31-01-1994

6166861 A

14-06-1994

US 5082706

21-01-1992

86286 T

15-03-1993

2002073 A

23-05-1990

0370689 A

30-05-1990

62700 B

22-02-1995

2189383 A

25-07-1990

141486 B

15-06-1998

US 5721136

US 5729963

EP 0506372

24-02-1998

NONE

24-03-1998

US
CN
DE
DE
EP
JP
WO

5648136

1190524
69601802
69601802

0838137
11509163

9703545

30-09-1992

US
CA
DE
DE
JP

5466532
2061973
69206457
69206457
5098240

15-07-1997
12-08-1998
22-04-1999
04-11-1999

29- 04-1998

17- 08-1999

30- 01-1997

14-11-1995
27-09-1992

18- 01-1996
11-07-1996
20-04-1993

Form PCJ7ISA/2 1 0 (patent family aroiei) (.My 1 992)

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Full text of "USPTO Patents Application 10610949"

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